Hi,
see
https://pve.proxmox.com/wiki/Hotplug_(qemu_disk,nic,cpu,memory)#Memory_Hotplug
2 possiblity:
add "memhp_default_state=online" to grub
or
add udev script
/lib/udev/rules.d/80-hotplug-cpu.rules
SUBSYSTEM=="cpu", ACTION=="add", TEST=="online", ATTR{online}=="0",
ATTR{online}="1"
When hotplug is enabled, only 1GB of "static" memory is enabled (to
boot the kernel,...).
Then the other memory modules, are hotpluggable, and by default are
offline.
Le samedi 26 août 2023 à 22:41 +0000, Anderson, Stuart B. a écrit :
> Enabling PVE Hotplug Memory for a Linux Guest (tested with PVE 7/8
> and EL8/9) results in default kernel parameters that are orders of
> magnitude smaller than without Hotplug. It appears that the Kernel is
> mistakenly setting defaults as if the guest has only 1GB of memory.
> Does anyone know how to get the same kernel defaults with Hotplug
> Memory enabled as for disabled? Is this a bug in PVE, QEMU, or the
> way Linux queries QEMU?
>
>
> For example, a PVE7/EL8 VM with 32GB of Hotplug Memory has a very
> small value of Max processes:
>
> [root@ldas-pcdev4 ~]# grep processes /proc/$(pgrep systemd-
> logind)/limits
> Max processes 2654 2654
> processes
>
> compared to disabling Hotplug Memory:
>
> [root@condor-f1 ~]# grep processes /proc/$(pgrep systemd-
> logind)/limits
> Max processes 127390 127390
> processes
>
>
> Presumably this is due to the following memory layout as seen by the
> kernel,
>
> #
> # With Hotplug Memory: 1 bank with a 1GB DIMM
> #
> [root@ldas-pcdev4 ~]# lsmem
> RANGE SIZE STATE REMOVABLE BLOCK
> 0x0000000000000000-0x000000003fffffff 1G online yes 0-7
> 0x0000010000000000-0x00000107bfffffff 31G online yes 8192-8439
>
> Memory block size: 128M
> Total online memory: 32G
> Total offline memory: 0B
>
> [root@ldas-pcdev4 ~]# lshw -class memory
> *-firmware description: BIOS
> vendor: SeaBIOS
> physical id: 0
> version: rel-1.16.1-0-g3208b098f51a-prebuilt.qemu.org
> date: 04/01/2014
> size: 96KiB
> *-memory
> description: System Memory
> physical id: 1000
> size: 32GiB
> capabilities: ecc
> configuration: errordetection=multi-bit-ecc
> *-bank
> description: DIMM RAM
> vendor: QEMU
> physical id: 0
> slot: DIMM 0
> size: 1GiB
>
>
> #
> # Without Hotplug Memory: 2 banks of of 16GB DIMM
> #
> [root@condor-f1 ~]# lsmem
> RANGE SIZE STATE REMOVABLE BLOCK
> 0x0000000000000000-0x00000000bfffffff 3G online yes 0-23
> 0x0000000100000000-0x000000083fffffff 29G online yes 32-263
>
> Memory block size: 128M
> Total online memory: 32G
> Total offline memory: 0B
>
> [root@condor-f1 ~]# lshw -class memory
> *-firmware description: BIOS
> vendor: SeaBIOS
> physical id: 0
> version: rel-1.16.1-0-g3208b098f51a-prebuilt.qemu.org
> date: 04/01/2014
> size: 96KiB
> *-memory
> description: System Memory
> physical id: 1000
> size: 32GiB
> capabilities: ecc
> configuration: errordetection=multi-bit-ecc
> *-bank:0
> description: DIMM RAM
> vendor: QEMU
> physical id: 0
> slot: DIMM 0
> size: 16GiB
> *-bank:1
> description: DIMM RAM
> vendor: QEMU
> physical id: 1
> slot: DIMM 1
> size: 16GiB
>
>
>
> P.S. Unfornately, this isn't fixed with PVE8 (with a newer QEMU) or
> updating to a newer EL9 kernel. Here is PVE8/EL9 VM with 233GB of
> Hotplug Memory showing the same problematic small value:
>
> [root@pcdev15 ~]# cat /etc/redhat-release
> Rocky Linux release 9.2 (Blue Onyx)
>
> [root@pcdev15 ~]# grep processes /proc/$(pgrep systemd-logind)/limits
> Max processes 2659 2659
> processes
>
>
> --
> Stuart Anderson
> [email protected]
>
>
>
>
> _______________________________________________
> pve-user mailing list
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>
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